1. Field of the Invention
This invention relates broadly to medical devices. More particularly, this invention relates to canalicular implants for use in the repair of a damaged or malformed lacrimal canaliculi.
2. State of the Art
The lacrimal canaliculus is the canal leading from the lacrimal punctum to the lacrimal sac which empties into the nose. The canaliculus can become lacerated as a result of injury. One common cause of this type of injury, particularly in children, is a scratch from an animal claw in the proximity of the eye. Other common causes of canalicular damage requiring reconstruction include car accidents, cancer, and canalicular stenosis.
Additionally, there is a condition in which there is a lack of fluid communication between the lacrimal sac and the nasal cavity. Such a condition is treated with a dacryosystorhinostomy (DCR) in which a new tear drainage channel is surgically constructed between the lacrimal sac and the nasal cavity. Furthermore, pediatric congenital nasolacrimal duct obstructions can occur in which the nasolacrimal duct does not fully form and open within a normal time frame, e.g., one year, after birth, and must be surgically opened. In both these situations, after reconstruction of or opening of the passageway it is desirable to maintain the passageway in the open configuration during healing such that after healing patency is provided.
It is therefore an object of the invention to provide a monocanalicular stent which can be temporarily inserted into the canaliculus and, if desired, into the nasolacrimal duct to aid in repair and healing of a lacerated, constructed, or opened canaliculus.
It is another object of the invention to provide a monocanalicular stent which provides a structure about which canalicular or nasolacrimal duct tissue can heal.
It is a further object of the invention to provide a monocanalicular stent which permits surrounding tissue to heal in a manner which after healing provides an open channel for drainage of fluid from the lacrimal sac into the nose.
It is also an object of the invention to provide a monocanalicular stent which can be relatively easily inserted by a physician into the nasolacrimal duct.
It is an additional object of the invention to provide a monocanalicular stent which is customizable in length by a physician depending upon the application and the anatomy.
In accord with these objects, which will be discussed in detail below, a monocanalicular stent is provided which includes a plug portion and an elongate tubing portion preferably molded with or coupled to the plug portion at approximately a ninety-degree angle.
The plug portion preferably includes a body portion, a neck portion, and a head portion, and an axial bore partially extending therein. The neck portion preferably includes an accordion-like construction, permitting the neck portion to bend, stretch, and collapse as necessary to maintain an anatomical fit at the vertical punctum. The head portion is preferably designed to have a low profile at the punctal opening.
The leading end of the tubing portion is preferably cut at an angle to create a leading surface which facilitates insertion of the stent into the nasolacrimal duct. The tubing portion extends substantially longer than the plug portion; for example, twenty times the length or more. According to a preferred embodiment, the tubing portion includes a pathway which extends the entire length thereof. According to another embodiment of the invention, the pathway of the tubing portion and the bore of the plug portion are in communication.
A delivery stylet is also provided and extends into the tubing pathway (and bore of the plug portion where such is in communication with the tubing pathway) and provides a tool by which the physician may handle the stent and insert it into the canaliculus or nasolacrimal duct.
Prior to use, the stent is cut to length, as necessary, and the leading end of the stent is tied closed with a suture. The stylet is then maneuvered to deliver the stent into a dilated punctal opening. The stent is then advanced through the canaliculus until the position of the plug portion is immediately above the punctal opening. The stylet is removed, and the plug portion is then manipulated into the punctal opening until the rim of the head portion is flush with the surface of the punctal opening.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.